Drafting-instrument.



To all 'whom t may concern:

IYBON E. STECZYNSKI, 0F CAMBRIDGE SPBINGSPENNSYLVANIA.

DRAWING INSTRUMENT.

spmnmmn of Letters rama.

Patented Oct. 16, 1917.

Appumlon mea rebmary 1e, 1917. serial mi. 149,079.

Be it known that I, MYRoN E. S'rnoz'rN- sKI, a citizen of the United States, residing at Cambridge Springs, in the county of Crawford and State of Pennsylvania, have invented new and useful Improvements in Drafting Instruments, of which the followin is a specification.

y invention relates to drafting instruments which are used in ruling and has for its objects; first, to provide an improved rulin instrument the component elements of w ich `are slidably related whereby one element may be moved'in relation to a stationary element in order that a scale on the moving element may be brought into proper registry with designated points of a drawing, and second, to provide a ruling instrument in which is incorporated a scale whereby the ordinary ruler may be dispensed with and a great saving of time and labor result.

I attain 'these objects by the mechanism illustrated in' the accompanying drawings, in whichz- Figure 1 is a top plan view of a T-square embodying my invention, v

Fig. 2 is an enlarged end elevation of the device illustrated in Fig. 1.

Like characters of reference parts in the various views.

In the drawings 1 designates the head of a T-square having a straight surface 2 for enga ement with the edge of a drawing boar A blade 3 is disposed at right angles to surface 2 of head 1 and is ailixed to head 1 as hereinafter described. Atransverse slot 4 is formed in the upper surface of head 1, the sides vand bottom of said slot being at right anglesl to the surface 2 and the said sides being parallel to each other. At the sides of slots 4 the parallel strips 5 are secured one at' each side by means of screws 6. The top surfaces of strips 5 are flush with top of head 1 and the opposing sides are -slanted upwardly 4and inwardly thereby making slot 4 wider at its bottom than at its to See Fig. 2. The ends of the edges of b la e 3 are formed to lit snugly into slot 4 and are adapted to slide therein. The upwardly and inwardly slanted sides of strips 5 retain the blade 3 within the slot 4.

indicate like Strips 5 are made of hard rubber or other wearresisting material. Blade 3 is composed of a center stilening element 7 with edgel members 8 of some transparent material such as Celluloid. Longitudinal channels 9 are formed in the bottom of slot 4 to decrease the friction between slot 4 4and blade 3.. A stud 10 is ailixed to head 1 at a convenient point and projects above thie upper surface of head 1. A lever l1 is pivoted on said stud 10 and is secured to stud 10 by a nut screw threaded upon said stud 10. Lever 11 extends over the end of blade 3 and terminates in a knob 12 for convenient manipulation. A metal bushing 13 is ailixed in blade 3 near the end thereof andhasA a transversely extending slot 14 formed in it. Aflixed to lever 11 and extending downwardly therefrom is a stud 15 which engages said slot 14. Thus by moving the lever 11 the blade 3 is moved longitudinally and parallel to its edges.

On the under side of edge members 8 of blade 3 scales are inscribed which are apparent from above through transparent members 8. The scales upon the opposite mem-J bers 8 have diiferent graduations in order that the instrument may be used on drawings requiring these dilt'erent graduations. A bushing 13 having a slot 14 is' affixed in the other end of blade 3 so that the first mentioned end ,of blade 3 may be 'removed from slot 4 and the other end inserted therein to bring the other of members 8 into working position so that its differently graduated scale may be used. In removin blade 3 from slot 4 the lever 11 is removed by unscrewing nut 16 from stud 10.

In the operation of the device it is used as an ordinary T-square to draw longitudi-- nal lines in various points in the drawings.

When a specified longitudinal line of given length is to be drawn from a specified point the device is moved until the edge of blade 3 lies in a proper plane for drawing the line and lever 11 is manipulated to move blade 3y until one' of the .unit marks of the scale on member 8 coincides with the specified point. The line is then measured olf on -the scale and drawn, thus saving the time 3 by reason of wear, thin strips of paper or other material may be placed between the sides of strips 5 and the sides of slot 4 by removing screws 46 and placing the paper in roper position and resecuring the strips 5 by replacement of screws 6. A snug-sliding joint may be thus constantly maintained.

Having thus fully described my invention, I claim:

1. In a device of the class described, a stationary element, having a slot therein and which is provided with a bottom and' arallelsides, strips afixed in said slot ad- ]acent the sides thereof and having 'their opposed sides longitudinally parallel and slantin upwardly and inwardly toward each o* er. and a. slidable element engaging the bottom of said slot and the4 slanting sides of said strips.

2. In a T-square, a stationary element, having la slot therein and which is provided with la bottom and parallel sides, strips affixed in said slots adjacent the sides thereof and having their o posed sides lon 'tudis nally (parallel and anting upwar land inwar ly toward each other, a slidab e element enga 'ng the bottom of said slot and the slant sides of said strips, a scale mounted on the slidable element, and a hand lever pivotally mounted upon the stationary element and engaging the slidable, element. In testimony whereof I aix my signature.

MYRON E. SITECZYNSKI. 

